I spent a summer there. Even playing solo free for all it was so much fun being the top scorer in a zone, having that little trophy next to your ship, and having people hunt you or get blasted. The ships vary, but there's a fast fighter that can one shot kill most things if you are a very good shot, and zoom by other ships on after burners with a little spin, dodging the return fire. That ship can also put a bullet through the openings in walls and bases and sometimes take out a defender. Even spending an entire summer at it, I wasn't the best shot by a long shot.

That's just my experience as well. There are many other types of ships like bombers with big explosive, slow shots with blast effect, and other ships that can have other players attach to them as turrets. If your team in the arena can escort a bomber safely to a base with some fighters, you can often nuke the enemy right through the walls and capture the flag there. Meanwhile if you are just piloting a fighter it's a big win to take out one of the turret ships. Then there's other ships like ones that can cloak and fire sneak attacks, etc..

I'd say that SubSpace and its predecessors were the first "haiku-competitives" -- a lineage that eventually resulted in DotA and League of Legends.

Essentially: distill gameplay to a relatively small number of rules + iterate balance until it's incredibly finely tuned + let the playerbase go nuts with whatever strategies they can come up with.

The attraction being that they're easy to pick up (few rules to learn) but incredibly deep (complex interactions and strategies).

Coupled with the fact that circa-late-90s, the idea of an MMO was still mind blowing. Games with friends and strangers?!

From memory, SubSpace also had a fairly addictive loot mechanic (tiered materials, item construction, randomly timed rare enemy spawns).